There are many patients suffering from disfunction of their organs caused by missing or reduced (atrophied) tissue, an example of which is the larynx.
The larynx is an important organ involved in the respiration, phonation and swallowing. In particular, deformation of the vocal cords brought about by lesions occurring thereon caused by cancer and other diseases, as well as their treatment and so forth, can cause phonation and swallowing disorders. These sequelae may be quite serious even after the primary disease has been completely treated.
In addition, deformation of the vocal cords is also caused by aging and excessive phonation.
This deformation is typically represented by, for example, partial defect, depression, atrophy or fibrous changes of the vocal cords. It prevents the vocal cords from complete closing during phonation and swallowing, and causes leakage of the air and misswallowing.
In the case of excessive leakage of the air, a large vital capacity is required for phonation, resulting in extremely hoarse voice and indistinct pronunciation, and creating a serious obstacle to social life due to impaired communication.
A treatment method consisting of injecting only collagen into peripheral tissue has been utilized for this tissue atrophy or arcuate deformation (and is used clinically for removal of skin wrinkles and vocal cord reconstruction).
However, since injected collagen is absorbed and eliminated in the body after about one month, in the case of the vocal cords, they return to their state prior to injection in an extremely short period of time, thereby preventing satisfactory phonation and prevention of misswallowing from being maintained.
In addition, frequency injection of collagen into the vocal cords places a considerable burden on the patient psychologically, physically and even financially.